Electric hoist



Fl LI STONE.

ELECTRIC HOIST.

APPLICATION FILED AUGZS. I9I9.

Fig. I.

Patented July 20, 1920.

Inventor:

F'r d L- Stone,

His Atto r-ney- UNITED 'ST'A'llES PATENT OFFICE.

FRED SVTQNE, or SCHENEGTAPY, YORK,- AssIe qR TO sem nar. ELECTBIG COMPANY, A conronar o'nor new Yon nLnc'r uc Horscr.

Specification of Letters Patent.

Patented July 20, 1920.

Application filed August 26, 1919. Serial No. 320,006.

To (ZZZ whom it may concern:

Be it known that I, FRED L. STONE, a sub-- ject of the "King of Great Britain, residing at Schenectady, in the county of Schenectady, State of New. York, have invented certain new and useful Improvements in Electric Hoists, of which the following is a specification. 7

My invention relates to electric hoists and the like and it provides improved means whereby the hoist brake may be controlled in a safe, reliable and efficient manner.

My invention 1s particularly useful in concase of amines-hoist, ofthe slope type where one or more cars are hauled up an incline,

when the hoist is lowering cars it is desirable that the brake be applied substantially simultaneously with thei'failure of power,

- but when the hoist is'operating. in the hoisting direction it is not desirable to apply the brake simultaneously with the failure of power, since the cars have considerable in ertia and will continue up the slope; for some considerable distance, depending upon the inclination er the slope and the'store d energy in the load being hoisted. The drum beingstoppechthe load being hoisted will eventually come to rest and startback down the slope so that when" the rope. has'been drawn taut, the rope will either break, pull out of the shackle, or the draw bars between the cars will break, so that the entire trip or-part of it will startdown the slope and cause a serious accident. V p Y 7 One of the ob ects of my invention is to provide improved means whereby on failure of power the brake will not be applied until after the speed of-the hoist has been considerably reduced. 'Prefer abl y the'application of the brake should occur simultaneously with the stopping of rotation of the hoistl drums, the arrangement being such, however, that during lowering, with or without the electric motor energized, failure of power reduced or the hoist known types ofbrakes.

. in which there is a double track slope with a loaded trip going up on one track and an empty trip going down on the other track,

the hoist brake will not be applied until the speed of the hoist has been very materially drum has stopped r0- tating. r

' For a better understanding of my inven tion, reference is had to the accompanying drawings wherein I have shown my inven-' nectionwith electric mine hoists, althoughtion embodied in concrete form for purposes ofillustration, and in which Figure 1 shows diagrammatically an electric hoisting systern provided with my invention, and Fig. 2

is a detail of- Fig. 1, showing'a part section of an over-running clutch which is adapted to drive in" one direction only.

Referring to Fig. 1, for purposes of illus-r tration I have'shown an electric motor 10 Ofrth induction type adapted to drive the hoisting drum 11 through the pinion and gear shown. The motor is energized from asource of'supply 12 by means of reversing cont-actors "13 and 14, the coil circuits of which are controlled by. means of a master controller 15, in a well-known manner. The motor is provided with a wound rotor with secondary resistance R which maybe varied inany suitable and well-known manner in orderto'va'ry thespeed'of the hoist. For

purposes of illustration I have shown a .fluid pressure brake but it will be understood by those skilled in 'the art that m invention is equally applicable to other wel The brake B shown is of the gravity set type and a fluid pressure releasing mechanism is provided. This mechanism comprises a piston '16 operating in a-cylinder 17 whichreceives a fluid under compression from the reservoir 18 through the rotary valve-mechanism 19. In the'pos'ition shown in the drawin' the valve is in the position in which the uid is exhausted from the cylinder 17 to atmosphere through theport 20 'An operating mechanism for effecting the appl cation and release ofjthe' brake B is provided, and this operating mechanism comprises a lever 21 fulcrumed at its mid-point and connected to thefoperating lever 22 of 'the valve 19 by.

means of alink 23. The plunger24 of a responsive device 26 of the well-known fiy ball governor type cooperates with the-lefthand end (if the lever 21. The lever 21 is biased to its upper position at which the brake is released, by means of the spring 21', The fly-ball governor is driven through bevel gears 27 from the shaft 28 to which the hoisting drum 11 and the brake B are connected. ,An over-running clutch 29, shown. 7 1n more detail in Fig. 2 is provided ior drlvingthe fly-ball governor only when the hoist isoperatmg in the hoisting direction. This over-running clutch comprises a ratchetwheel-30 connectedto the shaft 31 which drives the fly-ball governor and a sleeve 32 connected to the shaft 33 which is driven from the shaft 28 through thebevel gears 27. This sleeve 32 is provided with a plurality of rollers or balls 3 1. which cooperate with, the sleeve32 and the ratchet wheel 30- to drive the fly-ball governor when thehoist' is; operating inth'e hoisting direction but 1 the construction is such that when the hoist is operating in the lowering direction the rotatewwithout driving the ratchet wheel '30. This overrunning clutch is of anwellknown construction, and it is thougl'it that itneed not'be i'urtherdescribed:. if V 7 A s thusconstructed a and arranged, the

' operationof myinventionisasfollows; Letit be'assumedthatitzis desired toho'istthe" load, which for purposes of-illustration has net, thereby causing the .plunger-2 4 to The raised to its elevated positiom and the lever- 21 to be :tilted to the position indicated in dotted lines at 37'. The link-23 will thereby be: raised and the operating lever '22 'ofithe valve;.19 will/be turnedclockwise so that V fluid under 7 compression is (admitted to the I cylinderv 17 from the reservoir 18 through the pipes 38 and 39, thereby causingthe piston- 1,6 to'beraised andthe brake B to;

be-ire'leasedp I The controller 15- will be turned to the right so as toenergizeythe reversing- 100111130110114: to close and connect the motor C. lfi'to the source of supply 12. *--As,.soon as the lhoist begins rotating, the' fly-ba'll gover-L nor; 26 will becaused'to rotate through the rollers or balls 34 offlthe clutch '29-we'dgingi themselves between the-"sleeve 32 and ther-Z or tlie like and a brake for theysain e, of cam surfaces-of the ratchet wheel 30. 'The' fulcrum'of' the lever 21 will be'moved upfwarda slight distancefbut this will h'ave no efiect-on the brake-:13, since thebrake has :been previously released through the energi zationiof thecoil 25: If the-powershould 1 fail while the hoist is proceedingin the upward directiomthe coil 25 will be deenergized andthe plunger 2 1 will drop and tilt the lever 21 to the position indicated in dotted lines at'1 1O. The brake will not be applied immediately; however, since theflye ball governor 26 is still being rotated and the fulcrum of the lever 21 has not been moved downward far enoughto operate the valve 19 so as to exhaust the 'fiuidunder' compression from the cylinder 17 The ap-V plication of the brake Ywill'be delayed until i the fluid fromthe cylinder 17 \is exhausted" throughthe port 2010f the Valve-19 when the speed of the hoist" has been very-materiallyreduced or thehoist has been brought substantially, to rest through the; medium ofthe fly-ball; governor loweringthe lever To operate the'hoist in the. lowering direcsource of supply 12 so asnto operate in the reverse 1 direction; The Lily-ball governor 26 willbe at' restisince the construction of the ernor will not be driven The lever 21 will assume'the position indicated in dottedxlines at 37 at. which fiuidunder compression 21 to "the position shownjin the drawings.

over-running.clutch 29 i'ssuch that when the i hoist is operating in this direction'the gov rollers or balls 34: are in the position shown in Fig. 2 at. which the sleeve 32 is freeto admitted tothe cylinder 17 so as tot release 1 j the brake B. In casethe. powershould fall i when the hoist is operating in thefalowering V d irection the brake will be applied practically simultaneously-by reason of thefpluir ger2 1-of the no voltage protective electromagnet-droppingto its lower position, that showns-in the drawings. -Theij cylindenl'i' 1 will thereupon be connected to atmosphere through; the port 20, and the brake will "be applied' practically simultaneously; with the failureofpower: 1+

In casethe hoist is of the balang'ied type in which a trip of cars or other load :is being hoisted up" one slope and a trip ofucars or other load is being lowered simultaneously 1 clutch 29 will not be used, but the fly-ball governor 26will be connected'so as to'rotate.

decreased to the predetermined value;---.

KfVhatlIclaam as new and-:desireto secure Letters Patentiof the United-:statespisz V -on' another set of tracks, the over-running V 1'. The combinationwithi an electric hoist I 2 means for automatically applying the brake f onifailure of power, and means for delaying .th'e'appIicatiQn of the brake until the speed or the like and a brake for the same, automatically applied on failure of power, of automatic means for preventing the application of the brake until the speed of the hoist has decreased to a predetermined value.

3. The combination with an electric hoist or the like and a brake for the same, of means for automatically applying the brake 011 failure of power, and means operated responsively to the speed of the hoist for delaying the application of the brake on failure of power until the speed of the hoist has decreased to a predetermined value.

a. The combination with an electric hoist or the like and a mechanical brake for the same, of means operated responsively to the speed of the hoist and to a failure of power for delaying the application of the brake when the power fails until the speed of the hoist has decreased to a predetermined value.

5. The combination with an electric hoist or the like and a mechanical brake for the same, of automatic means operated responsively to the speed of the hoist during hoisting but unresponsive to the speed of the hoist during lowering for delaying the application of the brake until the speed of the hoist has decreased to a predetermined value when the power fails during hoisting, and for applying the brake simultaneously with a fail ure of power when the hoist is lowering.

6. The combination with an electric hoist or the like and an electromagnetically controlled mechanical brake for the same, of automatic means for applying the brake simultaneously with a failure of power when the hoist is lowering, and for delaying the application of the brake until the speed of the hoist has decreased to a predetermined value when the power fails during hoisting.

7. The combination with an electric hoist or the like and a brake for the same, of means for effecting an application of the brake comprising a lever biased to a position at which the brake is released, a speed responsive device operating on one end of the lever and a power responsive device operating on the other end of the lever, whereby in response to a failure of power the lever is moved against its bias to effect an application of the brake after the speed of the hoist has decreased to a predetermined value.

8. The combination with an electric hoist or the like and a brake for the same, of means for effecting the application of the brake comprising a lever biased to a position at which the brake is released, a speed responsive device operating on one end of the lever and a power responsive device operating on the other end of the lever, and means for operating the speed responsive device only when the hoist is operating in the hoisting direction, whereby in response to a failure in power the lever is moved against its bias to effect an application of the brake after the speed of the hoist has decreased to a predetermined value when the hoist is operating in the hoisting direction and an application of the brake is effected practically simultaneously with the failure of power when the hoist is operating in the lowering direction.

In witness whereof I have hereunto set my hand this 25th day of August, 1919.

FRED L. STONE. 

